Hack saw



Aprl 3, 1928.

` D. E. GOMMEL HACK SAW Filed Sept. 11, l924 A2. Sheets-Sheet Abril 3, 192s.

D. E. GOMMEL HACK SAW 2 Sheets-Sheet 2 Filed Sept. l1, 1924 attoznu Patented Apr. 3, 1928.

UNITED STATES PATENT OFFICE DEWEY E. GOMMEL, OF INDIANAPOLIS, INDIANA, ASSIGNOR TO E. C. ATKINS & COM- ."PANY, F INDIANAPOLIS, INDIANA, A CORPORATION `OF INDIANA.

HACK SAW.

Application filed September 11, 1924. Serial No. 737,144.v

My said invention relates to a power driven hack saw and it is an object of the same to provide improved and simplied means for driving a hack saw with strokesy proved machine,

Figure 2, a plan of the same,

Figure 3, a section on line 3-3 of Figure 1, and

Figure 4, a vertical cross section at the right-hand side of jaw 27 in Figure 1.

In the drawings reference character indicates the fixed frame of the machine said frame being provided with a pivot 11 for a lever 12 on which lever a pivot 13 is i provided which forms the fulcrum of a lever 14.

At its upper free end the lever 14 is connected by a pivot 14 to a link 15 and this in turn is pivoted to a frame 16 having depending arms 17 and 18 with means at the lower ends for supporting a hack saw blade 19. The frame 16 is supported for sliding movement lengthwise of the machine on a bar 20 fixed at one end to an upright 21 pivotally mounted on the main frame at 22. A brace 23 is connected at its forward end to the bar 20 and at its other end to the upright 21 said brace being provided at its forward end with a handle 24 by means of which the parts 20, 21, 23 may be moved on the pivot 22 carrying with them the frame 16 and the parts attached thereto. A brace 25 is connected to the brace 23`midway of its length and extends therefrom to the farthe corner of the upright 21.

The workholder is in the form of a vise and preferably comprises a fixed jaw 26 and a movable jaw 27 although both jaws may be movable if preferred. For moving the jaw 27 I have provided a hand wheel 28 and a rod 28 connected to the jaw 27 by screwthreads or other suitable means. A link 29 is pivoted at one end at 29 to the movable support 27 for the jaw 27 and at the other end is pivotally connected to the lever 12.

The lever 14 haspa slot to receive a slide 30 on a crank pin 31 said crank pin being oper-. ated by a shaft 32. This slot is shown as being formed in a bent arm of the lever but it will be understood that the lever may be straight or may be bent at various angles other than that shown.

For tightening the saw blade I have provided connections comprising 'a bolt 33 at one end of the blade, preferably held in fixed position by set screws. A bolt 34 flattened on each side` passes loosely through a depending arm 18 and has a nut bearing against a lever 35 through which the bolt also extends loosely. This lever is loosely fulcrumed at 36 against the depending arm 18. A bolt 39 at the other end of said lever has an eccentric extension 39 y head 40 by means of which the bolt may be turned to vary the position of the eccentric extension and thus bring the saw into alignment by swinging the lever about a horizontal pivot. The bolt 40 is held in place by a nut 40 and the eccentric extension 39 has a nut 41 threaded thereon by means of which the lever 35 may be locked on its fulcrum to tension the saw.

The jaws of the vice are pivotally aoljustable about points, or more accurately aboutv verticalk axes, in the same plane as the center line of the saw cut so as to utilize the full length of the blade at all times and at all angles. With this object in view slots 42 and 43 are formed in the parts supporting the adjustable jaws 26 and 27, eachfpair of slots beingr concentric and' being formed on arcs drawn about the pivot points or axes of the respective jaws. Each jaw is provided with a pair of guide-pins or bolts 44 4projecting into the respective slots 42 and 43 and adapted to secure the jaws in adjusted position in any desirable or conventional manner. By adjusting the position of the jaws it is possible to make a cut at right-angles to the length of the work as in Figure 2 or at any angle through a wide range.

Figure3 illustratesadjustments for taking up wear between the saw frame 16 and the support 20. The saw frame comprises outer and inner members 45 and 46 one of which may. overlap the other as shown in said figure. These parts are held together by screws 47 and nuts 48. A slight clearance is left between the meeting edgesvof and a squared y lll the two parts 'at 49 'so that the lnuts 48 may be gradually tightened to `draw the parts 45 and 46 down on the bar 20. A shim 50 is entered between the bar 2O and the overhanging arm of the rarne member 45. A series of screws 51 extend through fholesin said arm into engaging relation with the shim 50 whereby the screws may be turned down at necessary intervals .for taking up wear between the shim and the bar. Nuts 52 fare provided vlroi locking Esaid bolts fin adjusted-position-` 'The movable support 27 for the jaw 27 has parallel iianges `at opposite `sides (Fig.

. v4) extending over adjacentparts of the base, whereby `it `is guided iorslidingadjustinent by the threaded `rod '28. Braekets "53 vareinoun'ted on the respective lguiding portions of fthe frame atoppositeV sides a pivot F54 ttor a lever 55 having at its Jfree end a Iroller `resting on the periphery fi of a camfon the shafti32. The cam moves the lever up and -fdown about its `pivot as the Lshaft rotates `a-ndthereby `operatesaa flon- `upper lpart includes a piston 59 within "the cylinder. `Any convenient opening, with or without valves may be provided for `ad mitting lair or liquid in Asufficient quantity so that whenthellever 14 swings to the right lto retractithe saw, the-saw irame "and guide are swunglupward aboutithe pinfot-22` to' prevent engagement of the saw `with the `work in lits `retracting movement. The `parts Aare so proportioned that sufficient fluid will 'have lescaped rby -the time the` saw fra-ine Areaches the rearward limit 'of 1its movement "to permit thesawto again-engage the `work atlthe beginning o'f the ycutting stroke.

In iaddition to the parts `heretofore desoribedthe shaft B2i carries an eccentric 60 v operating ithe ipiston of afpurnp 6l of conventionalfcharaeter lfor supplying, cooling, and `eutti'ng compounds vto the sawv out.

din the use fof my device the jawsfwill `be `op'enedito receivefa piece of work 42 andthe jaw `V 27 `will lbe brouglit to Iholding position by manipulation of Athe hand #wheel 28. The variation in `position o the `jaw 27 causes movement of the link 29 and the lever 12ithereby movingthe ulerum 13 and thev lever 314 brelatively to Ithe shaft 32 and the parts carried thereby. By this arrange ment 'the stroke of Ethe saw is varied according tothe size of the work so las to use the "full length of fthe saw under all conditions. 'The pivot '14 returns to the saine positionat ltheiendo'f each stroke so thatit isneeessary only to move onevise jaw to secure the-desired results.

lV'ai'ious modifications of my device `willbe obvious `toV those skilled the art andthere fore I `do not limit myself to the specific forni of the invention shown in the draw- 4ingsand `described in the specification but only as indicated 4in Athe appended claims.

'For example the shaft 32 might 'be moved instead of the fulcrum 13 and many other changes may be made without departing- Afrom the spirit of the invention. A hack saw is shown in the drawings, but features of `the 1 invention `niaylbe used ainiother sawing upon said guide, alever fpivotally mounted underneath the tablefand having its/upper end extending above V'the Ctable and 'orniedi with fan 'angular `slotted arm Ibeneath .fthe table, a sliding; block mounted in said slotio'f said arm, a link connecting fthe upper lend ot said lever with the sawa ipower shaft mounted beneath? theftable adj acenti the llever, means connecting said 1power`shaft iwith the sliding block in the slotted angular arin of' said lever, a. work-holding vise mounted on saidtable one jaw of which `is fixed-andi the other of which is slidable, `:a :conneo `machines within the scopeiof iinyinvention. `Having Ithus :fully .described my said fintionbetweenlthe lower endo said slidable Y jaw and the ipower shalit for operating the saine, and smeans yconneoting said slidable jaw rwith the saw iframe for controlling the j length of its stroke as said movable fj'aw adjusted, all` substantially fas set rforth.

`2. Thefcombination oflatableua saw guide pivotedion one endet said table, a saw slid- `ably mounted yon said Asaw guide, a 'work holder comprising .a xed ijaw fand `amm able jaw inountedon` said tablezfinia position to hold ithe workA to -`be `out by i said saw, .ma drive shaft mounted `transversely beneath said table, abellorank leverpivotednisubstantially the horizontal fiplaneyof said :drive shaft and `having `one arm 'slotted `and lisposed in substantially horizontal position and engaging an eccentric .carried by said y drive shaft, .la connection between said .lee-

centric andsaid movable jaw, and ia flink connecting *the opposite -end Aof fsaid bell crank lever `with Vsaid saw, the connection between the Vbell vcrank ilever and Ethe shait being such that the Lsaw willbe moved fin one direction `at a -slow lspe'edf andiin a\\rever'se direction at *an accelerated speed, `substantially as set forth.

3. The'combination oatable', aisaw guide pivoted onone end of saidtableyarsaw slid-- ably `mounted yon `said lsaw guide, l`a work holder comprisingfa fixed jaw and a=mov-able jaw mounted on said `=tablesin :a position #to hold'the workrto becut byy said saw, afdrive shaft mounted transversely` beneath said Hifi table, a bell crank lever pivoted in substantially the horizontal plane of said drive shaft and having one arm slotted and disposed in subst-antially horizontal position and engaging an eccentric carried by said drive shaft, a connection between said eccentric and said movable jaw, a link connecting the opposite end of said bell crank lever with said saw, the connection between the bell crank lever and the shaft being such that the saw will be moved in one direction at a slow speed and in a reverse direction at an accelerated speed, substantially as set forth. j

4. The combination of a table, a work holder adjustably mounted on said table, a saw guide pivotally mounted on one end of the table, a saw slidable on said saw guide, a shaft mounted transversely beneath the table, a cam mounted on said shaft, a pin mounted eccentrically of said cam, a lever pivoted adjacent the bottom of the table below the horizontal plane of said drive shaft and having its upper ends extending upwardly to substantially the same distance above the drive shaft, a link connecting the u per end of said lever and the work holder W ereby the lever will be rocked on its pivot when the work holder is moved into engagement with Work of various sizes, a bell crank lever fulcrumed substantially midway on the iirst mentioned lever and having one end slotted for accommodating the pin on the cam whereby such slotted end will be operated for reciprocating the bell crank lever, a link connecting the bell crank lever with said saw, a pivotally mounted arm engaging the periphery of the cam on the drive shaft and adapted to be oscillated by said cam, a

dash pot having one end connected to said pivotally mounted arm and having its other end connected to the saw guide, the arran ement being such that when the drive sha t is rotated the pin will move outwardly in the slotted end of the bell crank lever in a semi-circle and operate the saw at a slow speed and will move in the inner end of said slotted arm of the bell crank lever in a semi-circle and operate the saw at a greater rate of speed. and at substantially the same time the pivotally mounted arm and dash pot will elevate the saw guide and saw, substantially as set forth.

5. In a power hack saw the combination of a table, a work-holder mounted on said table on supports adapted to adjust said workholder in the arc of a circle said work-holder consisting of two jaws one mounted in fixed position and the other adapted to move, .a lever pivotally mounted underneath the table and formed with an angular slotted arm, the upper end of said lever being conneoted to the saw frame, a power shaft mounted beneath the table adjacent to said lever, a sliding block mounted in the slot of said slotted arm of said lever and an operating connection between said slotted arm and the movable jaw and also the saw frame whereby adjustment of said movable jaw controls the length of the stroke of the saw, regardless of in what position the movable jaw may be, substantially as set forth.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana this 27th day of August, A. D. nineteen hundred and twenty-four. Y

DEWEY E. GOMMEL. 

